Silicone rubber adhesive films are known. For example, Japanese Laid Open Patent Application Numbers (hereinafter Kokai) Hei 1-197587 (equivalent to U.S. Pat. No. 4,918,126) and Kokai Hei 2-28280 (equivalent to U.S. Pat. No. 5,023,288) provide silicone rubber adhesives comprising silicone rubber compositions in which the main components are alkenyl-functional organopolysiloxane gum, organohydrogenpolysiloxane, wet-method hydrophobic reinforcing silica, platinum-type compound catalyst, and adhesion promoter. These silicone rubber adhesives are characterized by simplicity in handling and excellent workability and, when applied to substrates that have smooth surfaces, e.g., glass and metal substrates, can tightly bond these substrates into a single article.
However, there have been problems with these silicone rubber adhesives; for example, oil may exude onto the surface during long-term storage and, depending on the curing conditions, voids may be produced at the interface between the substrate and the cured adhesive layer, resulting in a decline in adhesive strength.